ath9k: fix BTCoex configuration for SOC chips

Allow to set wl_active_time and wl_qc_time for SOC chips, also adjust
bt_time_extend and bt_first_slot_time.

Signed-off-by: Miaoqing Pan <miaoqing@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>